LED is great if you have heat problems, it can produce the same amount of light as HID with 60%-80% of the power of HID, so less power is needed to produce the same amount of light.
The heat is proportional to power, 60% power, 60% heat. As GBAUTO pointed out, LED doesn't heat the plants with infrared like HID does, so plants under LED like higher air temperature, around 82-84 F.